A pressure-sensitive sheet used in a magnetic disk drive has been known as is described in Patent Document 1. An example of such a pressure-sensitive sheet includes a cover seal. The cover seal is used to cover a small gap (at a joint) provided between a box-shaped base member of the magnetic disk drive and a plate-shaped cover member attached to the base member.
Thus, airtightness of the magnetic disk drive is ensured by using the pressure-sensitive sheet and foreign substances such as moisture and siloxane compound that may adversely affect the magnetic disk drive are less likely to enter the magnetic disk drive.
To improve properties of the magnetic disk drive, inside of the magnetic disk drive may be filled with low density gas such as helium gas instead of air as is described in Patent Document 2. If the inside of the magnetic disk device is filled with gas having lower density than air, the disturbance of an air flow that may be caused in driving of the magnetic disk drive is less likely to occur and the properties of the magnetic disk drive are improved.    [Patent Document 1] Japanese Unexamined Patent Application Publication No. 2014-162874    [Patent Document 2] Japanese Unexamined Patent Application Publication No. 2010-3356